Add an example of location referring to a search parameter which does not need quotes (not using a modifier). Clarify the language so it is clear this section talks about the fhirpath paths used in the "expression" element, not the deprecated "location" element. Add a note saying that if the convention in the spec is used (where headers are capitalized and search parameters start with a lower case), no collisions can occur, and the implementers are encouraged to stick to the same convention.